Giovanni Montini

Prevalence of Mutations in Renal Developmental Genes in Children with Renal Hypodysplasia: Results of the ESCAPE Study

Renal hypodysplasia (RHD) is characterized by a reduced nephron number, small kidney size, and disorganized renal tissue. A hereditary basis has been established for a subset of affected patients, suggesting a major role of developmental genes that are involved in early kidney organogenesis. Gene mutations that have dominant inheritance and cause RHD, urinary tract anomalies, and defined extrarenal symptoms have been identified in TCF2 (renal cysts and diabetes syndrome), PAX2 (renal-coloboma syndrome), EYA1 and SIX1 (branchio-oto-renal syndrome), and SALL1 (Townes-Brocks syndrome). For estimation of the prevalence of these events, an unselected cohort of 99 unrelated patients with RHD that was associated with chronic renal insufficiency were screened for mutations in TCF2, PAX2, EYA1, SIX1, and SALL1. Mutations or variants in the genes of interest were detected in 17 (17%) unrelated families: One mutation, two variants, and four deletions of TCF2 in eight unrelated patients; four different PAX2 mutations in six families; one EYA1 mutation and one deletion in two patients with branchio-oto-renal syndrome; and one SALL1 mutation in a patient with isolated RHD. Of a total of 27 patients with renal cysts, six (22%) carried a mutation in TCF2. It is interesting that a SIX1 sequence variant was identified in two siblings with renal-coloboma syndrome as a result of a PAX2 mutation, suggesting an oligogenic inheritance. Careful clinical reevaluation that focused on discrete extrarenal symptoms and thorough family analysis revealed syndrome-specific features in nine of the 17 patients. In conclusion, 15% of patients with RHD show mutations in TCF2 or PAX2, whereas abnormalities in EYA1, SALL1, and SIX1 are less frequent.

Febrile Urinary Tract Infections in Children

Approximately 7 to 8% of girls and 2% of boys have a UTI during the first 8 years of life. Not all UTIs involve the kidney, but acute pyelonephritis is one of the most common serious bacterial infections in children. This review summarizes diverse views on this topic.

Prediction and treatment of recurrent focal segmental glomerulosclerosis after renal transplantation in children

The recurrence of focal segmental glomerulosclerosis (FSGS) after renal transplantation has a potentially detrimental course toward the loss of renal function. To identify prognostic markers for recurrence and efficacy of treatment, we evaluated the outcome of 32 renal allografts in 29 pediatric patients with FSGS who underwent transplantation from 1987 to 1998 in the North Italy Transplant program. Recurrence was observed in 15 of 29 patients (52%) after the first transplant and in 3 of 3 patients (100%) after the second graft. No significant differences in sex, age at FSGS onset, age at transplantation, or length of dialysis were noted between patients with recurrent and nonrecurrent FSGS. Those with recurrence originally developed end-stage renal failure faster (3.9 years) than those without recurrence (6.2 years). Pretransplantation serum samples from 25 patients were tested in an in vitro assay that evaluates glomerular permeability to albumin. FSGS recurred in 11 of 13 children who tested positive for the permeability factor and in 4 of 12 patients with a negative test result; the odds ratio for developing recurrence was 10.99 (95% confidence limit, 1.6 to 75.47) in the former group. The immediate onset of proteinuria after transplantation was a negative prognostic factor for the outcome; 6 of 9 patients in whom proteinuria appeared within 2 days of transplantation returned to dialysis in less than 24 months. In 9 of 11 patients who were treated with plasmapheresis plus cyclophosphamide after recurrence, proteinuria was successfully reversed and persistent remission was obtained in 7 patients. These data show that the glomerular permeability test has a significant predictive value for the recurrence of proteinuria in children with FSGS who have received a renal allograft. Of the clinical parameters considered, only the duration of disease was significantly different in patients with recurrent versus nonrecurrent FSGS. Treatment with plasmapheresis plus cyclophosphamide can be effective in the control of FSGS relapse after renal transplantation.

Infantile encephalomyopathy and nephropathy with CoQ10 deficiency: a CoQ10-responsive condition.

Coenzyme Q10 (CoQ10) deficiency has been associated with various clinical phenotypes, including an infantile multisystem disorder. The authors report a 33-month-old boy who presented with corticosteroid-resistant nephrotic syndrome in whom progressive encephalomyopathy later developed. CoQ10 was decreased both in muscle and in fibroblasts. Oral CoQ10 improved the neurologic picture but not the renal dysfunction.

Is Serum Cystatin C a Sensitive Marker of Glomerular Filtration Rate (GFR)? A Preliminary Study on Renal Transplant Patients

Human cystatin C is a basic low molecular mass protein (13,359 Dalton) freely filtered through the glomerulus and almost completely re-absorbed and catabolized by proximal tubular cells. We measured serum cystatin C in 38 kidney transplant patients (23 males, 15 females) aged between 6 and 32 years. To assess renal function, serum and urinary creatinine were also determined in all patients, and creatinine clearance was finally calculated. Cystatin C was determined by a particle-enhanced turbidimetric assay, and creatinine was measured by gas chromatography-mass spectrometry. To compare the diagnostic efficiency of cystatin C with that of creatinine, inulin clearance was performed on 12 renal transplant patients, and receiver operating characteristic (ROC) analysis was applied. The results of this study demonstrate that serum cystatin C significantly increases in renal transplant patients with reduced creatinine clearance (< 70 mL/min per 1.73 m2) and that the diagnostic accuracy of serum cystatin C is better than of serum creatinine. Cystatin C may be utilized as a very marker of reduced GFR.

Efficacy, safety and pharmacokinetics of candesartan cilexetil in hypertensive children from 1 to less than 6 years of age

Background Few antihypertensive drugs are available in appropriate formulations for infants. Method We investigated candesartan cilexetil liquid suspension in a 4-week, randomized double-blind dose-ranging study followed by a 1-year open-label treatment phase (NCT00244621). The drug was administered at 0.05, 0.2 or 0.4 mg/kg per day in 93 hypertensive children aged 1–5 years, of whom 74 had underlying renal disorders. Results A single-dose pharmacokinetic profile was obtained in 10 patients. At 4 weeks, SBP declined dose dependently by 6, 9 and 12 mmHg in the three dose groups (P = 0.01), and DBP by 5, 8 and 11 mmHg (P = 0.03). During the 1-year follow-up, responder rates (both SBP and DBP < 95th percentile) ranged from 48.2 to 54.1%. Candesartan lowered the blood pressure regardless of age, sex, BMI or cause of hypertension. The pharmacokinetic profile was independent of age, sex and weight, and was similar to that in older children and adults. In participants with proteinuric renal disease (urinary albumin/creatinine ratio >30 mg/g), a 57% median decline in albumin/creatinine ratio was observed at 4 weeks, which was dose related (P = 0.007) and persisted with long-term administration. There were no notable electrocardiographic or laboratory abnormalities. A mild decline in estimated glomerular filtration rate observed at 4 weeks was not progressive with long-term dosing. Candesartan was generally well tolerated; two patients withdrew for adverse events (fatigue and worsening glomerulopathy). One patient died, probably from acute-on-chronic renal failure. Conclusion Candesartan cilexetil dose-dependently decreases blood pressure and albuminuria in hypertensive infants and is generally well tolerated.

Mitochondrial dysfunction in inherited renal disease and acute kidney injury

Mitochondria are increasingly recognized as key players in genetic and acquired renal diseases. Most mitochondrial cytopathies that cause renal symptoms are characterized by tubular defects, but glomerular, tubulointerstitial and cystic diseases have also been described. For example, defects in coenzyme Q10 (CoQ10) biosynthesis and the mitochondrial DNA 3243 A>G mutation are important causes of focal segmental glomerulosclerosis in children and in adults, respectively. Although they sometimes present with isolated renal findings, mitochondrial diseases are frequently associated with symptoms related to central nervous system and neuromuscular involvement. They can result from mutations in nuclear genes that are inherited according to classic Mendelian rules or from mutations in mitochondrial DNA, which are transmitted according to more complex rules of mitochondrial genetics. Diagnosis of mitochondrial disorders involves clinical characterization of patients in combination with biochemical and genetic analyses. In particular, prompt diagnosis of CoQ10 biosynthesis defects is imperative because of their potentially reversible nature. In acute kidney injury (AKI), mitochondrial dysfunction contributes to the physiopathology of tissue injury, whereas mitochondrial biogenesis has an important role in the recovery of renal function. Potential therapies that target mitochondrial dysfunction or promote mitochondrial regeneration are being developed to limit renal damage during AKI and promote repair of injured tissue.

The Impact of Kidney Development on the Life Course: A Consensus Document for Action

Hypertension and chronic kidney disease (CKD) have a significant impact on global morbidity and mortality. The Low Birth Weight and Nephron Number Working Group has prepared a consensus document aimed to address the relatively neglected issue for the developmental programming of hypertension and CKD. It emerged from a workshop held on April 2, 2016, including eminent internationally recognized experts in the field of obstetrics, neonatology, and nephrology. Through multidisciplinary engagement, the goal of the workshop was to highlight the association between fetal and childhood development and an increased risk of adult diseases, focusing on hypertension and CKD, and to suggest possible practical solutions for the future. The recommendations for action of the consensus workshop are the results of combined clinical experience, shared research expertise, and a review of the literature. They highlight the need to act early to prevent CKD and other related noncommunicable diseases later in life by reducing low birth weight, small for gestational age, prematurity, and low nephron numbers at birth through coordinated interventions. Meeting the current unmet needs would help to define the most cost-effective strategies and to optimize interventions to limit or interrupt the developmental programming cycle of CKD later in life, especially in the poorest part of the world.

A developmental approach to the prevention of hypertension and kidney disease: a report from the Low Birth Weight and Nephron Number Working Group

In 2008, the World Health Assembly endorsed the Global Noncommunicable Disease (NCD) Action Plan based on the realization that NCDs caused more deaths than communicable diseases worldwide. 1 This plan strongly advocates prevention as the most effective strategy to curb NCDs. The “Life Course Approach”, also recently highlighted in the Minsk Declaration, reflects the increasing recognition that early development impacts later-life health and disease. 1,2 Optimization of early development offers the opportunity for true primary prevention of NCDs. Developmental programming in the kidney has been recognized for over 2 decades but its contribution to the global burden of kidney diseases remains underappreciated by policy makers. 3 Given the many factors known to impact fetal kidney development, including maternal health and nutrition, exposure to stress, poverty, pollutants, drugs and infections during gestation, 3 a holistic strategy to prevent such programming effects is consistent with the “Life-Course” approach and aligns with the United Nations Sustainable Development Goals (SDG) to foster health. 2,4 Chronic kidney disease (CKD) is an important contributor to the NCD burden that has been relatively neglected in the Global NCD Action Plan, despite CKD being a major cause of hypertension, and a major risk multiplier of cardiovascular disease 1,5 While the prevalence of CKD in many lower-income countries remains unknown, CKD is more prevalent among disadvantaged populations within industrialized nations, e.g. African Americans and Aboriginal Australians. 6 People receiving dialysis or transplantation are projected to double from 2.6 million in 2010 to 5.4 million in 2030. 7 Between 2.3 and 7.1 million adult people died from lack of access to dialysis and transplantation in lower-income countries in 2010. 7 Given the clinical consequences and often prohibitively high costs of treatment, prevention and early detection are the only sustainable solutions to address this growing global burden. To address the neglected issue of developmental programming of kidney disease and hypertension, a multidisciplinary workgroup, including international expert obstetricians, neonatologists and nephrologists (see Appendix), was convened. We argue that the Global NCD Action Plan does not adequately address the impact of developmental origins of NCDs which is globally but is particularly important in low- and middle-income countries (LMICs) where developmental risk is highest and the burden of NCDs is growing fastest. 8 The working group identified the need to raise awareness of the role of developmental programming in renal disease, and suggests locally adapted preventive strategies that could have long-term benefits on health and heath cost savings worldwide, integrating obstetrical, neonatal and nephrology perspectives.

Results of surgical treatment for renovascular hypertension in children: 30 year single centre experience

BACKGROUND We retrospectively reviewed the medical records of all patients who underwent surgery as part of the treatment of renovascular hypertension (RVH) at our centre between 1979 and 2008. Patients. Thirty-seven children (65% male) with a median age of 7.6 (0.4-17.9) years were identified with a median systolic blood pressure (SBP) of 140 (105-300) mm Hg prior to surgery. Bilateral renal artery stenosis and intra-renal disease were present in 19 (51%) patients, mid-aortic syndrome in 15 (40%), involvement of visceral arteries in eight out of 35 (23%) and coexisting cerebral disease in eight out of 30 (26%) investigated patients. RESULTS Surgical procedures (n = 53) included (i) nephrectomy (18, of which two unplanned and two secondary due to technical failure), (ii) renovascular surgery on the renal arteries (28, of which 18 had autologous surgery and 10 synthetic grafts inserted for revascularisation) and (iii) aortic reconstruction with (6) and without (1) a synthetic graft. Post-operative complications were haemorrhage (5), septicaemia (5) and chylous ascites (1). There were no perioperative deaths; two children died during follow-up. The SBP post-surgery improved to a median value of 116 (range 90-160) mm Hg. Twelve months after surgery, 16 (43%) children had normal blood pressure without treatment, 15 (41%) normal or improved on one to four antihypertensive drugs and four (11%) unchanged; no data were available for two (5%) children. CONCLUSION Surgery effectively treated the hypertension of 90% of our children, when performed in conjunction with medical therapy and interventional radiology. In spite of aggressive surgical treatment, RVH is sometimes a progressive disease.